IT9020008A1 - SELF-EXTINGUISHING POLYMERIC COMPOSITIONS - Google Patents

Abstract

Described are self-extinguishing polymeric compositions comprising: a) from 90 to 40 parts by weight of thermoplastic polymer, or of polymer having elastomeric properties; b) from 10 to 60 parts by weight of one or more derivatives of 2,4,6-triamino-1,3,5-triazine which derivatives are salified and have the general formula (I): <CHEM> wherein the radicals R and R1 to R5 are as defined in claim 1. Optionally, said polymeric compositions may also comprise minor quantities of ammonium phosphates and/or amine phosphates.

Description

it is replaced by a heterocyclic radical bonded to the alkyl chain through the nitrogen atom;

or in formula (I) at least one of the groups:

it is replaced by a heterocyclic radical linked to the triazine ring through the nitrogen atom;

the other radicals from R to R5, equal or different from each other, have the aforementioned meaning or are:

Optionally, the polymeric compositions can comprise reduced amounts of ammonium or amine phosphates.

* * * * *

The present invention relates to self-extinguishing compositions based on thermoplastic polymers or with elastomeric properties, especially olefinic polymers or copolymers, containing salts of triazinid compounds, optionally in combination with reduced quantities of ammonium or amine phosphates.

Various solutions are known in the art to reduce or eliminate the combustibility of polymers. Some of these solutions are based on the use of metal compounds, especially antimony, bismuth or arsenic, in combination with partially halogenated and thermally unstable organic compounds, such as chlorinated paraffin waxes.

Other solutions are based on the use of substances capable of producing intumescence. Intumescent formulations generally consist of the polymer and at least three main additives: one essentially phosphorated, the purpose of which is to form an impermeable semi-solid glassy layer during combustion, essentially consisting of polyphosphoric acid, and to activate the process of formation of the 'intumescence; a second containing nitrogen which fulfills the functions of foaming agent and a third containing carbon which functions as a carbon donor for the formation of an insulating cellular carbonaceous layer (char) between polymer and flame.

Examples of intumescent formulations of this type are those reported by patents: USA 3.810.862 (Phillips Petroleum Co.) based on melamine, pentaerythritol and ammonium polyphosphate, USA 4.727.102 (Vamp S.r.l.) based on melamine d anurate, of a hydroxyalkyl derivative of isocyanuric acid and ammonium polyphosphate, and from the published patent application W0 85/05626 (Plascoat U.K. Limited) based on various compounds of phosphorus and nitrogen including, in particular, a combination of melamine phosphate, pentaerythritol and ammonium polyphosphate.

In more recent formulations, together with the use of an organic or inorganic compound of phosphorus, an organic compound containing nitrogen has been used, generally an aminoplastic resin obtained by condensation of urea, melamine or dicyandiamide with formaldehyde.

Examples of formulations with two additives are those reported in US patents 4,504,610 (Montedison S.p.A.) based on oligomeric derivatives of 1,3,5-triazine and ammonium polyphosphate and European 14,463 (Montedison S.p.A.) based on organic compounds selected from benzylguanamine and reaction products between aldehydes and various nitrogenous cyclic compounds, in particular benzylguanamine-formaideide copolymers, and ammonium polyphosphate.

It is also possible to obtain self-extinguishing compositions using single-component additives, containing both nitrogen and phosphorus in the organic molecule, as described in US patent 4,201,705 (Borg-Warner Corp.).

These intumescent retardant systems give the polymer that contains them the property of giving rise to the formation of a carbon residue following a fire or the application of a flame. Retardant systems of this kind have numerous advantages: absence of corrosion phenomena in the machinery in which the polymers are processed, lower smoke emission than systems containing metal compounds and halogenated hydrocarbons, and above all the possibility of giving the polymers satisfactory flame-retardant properties. with a smaller amount of total additive and therefore without an excessive decay of the mechanical properties of the polymers themselves.

The Applicant has now surprisingly found that it is possible to confer satisfactory flame retardant properties to the aforesaid polymers by using one-component additives which allow to obtain polymeric compositions free from ammonium or amine phosphates or excellent flame retardant properties by using together with the aforementioned additives a quantity of phosphates of ammonium or of a much lower amine than in the prior art.

The Applicant has also surprisingly found that it is possible to obtain such excellent results by using phosphorus-nitrogenous compounds with an extremely simple structure, based on derivatives of 2,4,6-triamino-1,3,5-triazine salified with an acid containing the phosphorus. , and with good stability to heating, thus maintaining a high flame retardant activity even following the hot working processes of the polymeric compositions containing them.

The use of the above unsaltified 2,4,6-triamino-1,3,5-triazine derivatives of general formula (I) in combination with ammonium or amine phosphates is described in copending Italian patent application n ° 21066 A / 89 in the name of the Applicant.

As previously mentioned, saline derivatives of 2,4,6-triamino-1,3,5-triazine (melamine) containing phosphorus, which can be used as additives for self-extinguishing compositions in various polymeric matrices, especially polymers, are known in the art. Such compounds, such as for example melamine phosphate and melamine pyrophosphate, require the presence of other additives to carry out their action as flame retardants, especially a component containing the carbon necessary for the formation of the insulating cellular carbonaceous layer (char ) such as for example a polyol (pentaerythritol, dipentaerythrite, tripentaerythrite).

On the contrary, the compounds of the present invention find application in the formulation of polymeric materials as flame retardant additives of the "char-forming" intumescent type without the aid of other additives.

The compositions object of the present invention also have the advantage of giving rise, in the event of a fire, to a very moderate and non-obscuring emission of fumes.

More specifically, the compositions object of the present invention comprise:

a) from 90 to 40 parts by weight of a thermoplastic polymer or polymer with elastomeric properties;

b) from 10 to 60 parts by weight, preferably from 12 to 40, of one or more compounds derived from 2,4,6-triamino-1,3,5-triazine, salified with an oxygenated phosphorus acid, called derivatives of 2,4,6-triamino-1,3,5-triazine having the general formula (I):

it is replaced by a heterocyclic radical linked to the alkyl chain through the nitrogen atom and optionally containing another heteroatom preferably selected from 0, S, N;

it is replaced by a heterocyclic radical linked to the triazine ring through the nitrogen atom and possibly containing another heteroatom preferably selected from 0, S, N;

having general formula (II):

limerics object of the present invention can be added thereto from 1 to 25 parts by weight of one or more ammonium phosphates or an amine in substitution of an equal number of parts by weight of component (b).

Examples of radicals from R to R ,. included in the general formula {I) are:

methyl; ethyl; propyl; isopropyl; n-butyl; isobutyl; terbutyl; n-pentyl; isopentyl; n-slender; ter-thin; octyl; tert-octyl; decile; dodecyl; octadecile; ethenlle; propenyl; butenyl; isobutenyl; exenile; get them; cyclohexyl; propylcyclohexyl; butn ciciohexyl; decylcyclohexyl; hydroxycyclohexyl; hydroxyethylcyclohexyl; 2-hydroxyethyl; 2-hydroxypropylene; 3-hydroxypropyl; 3-hydroxybutyl; 4-hydroxybutyl; 3-hydroxypentyl; 5-hydroxypentyl; 6-hydroxiesi1e; 3-1 hydroxy-2,5-dimethylhexyl; 7-hydroxyeptyl; 7-hydroxyoctyl; 2-methoxyethyl; 2-methoxy propyl; 3-methoxypropyl; 4-methoxybutyl; 6-methoxlesyl; 7-metos siepti1e; 7-methoxyotti1e; 2-ethoxyetieth; 3-ethoxypropyl; 4-ethoxybutyl; 3-propoxypropylene; 3-butoxypropylene; 4-butoxybutes 1e; 4-isobutoxybutyl; 5-propoxypenties; 2-cyclohexyloxyethyl; 2-ethenyloxyethyl; 2- {N, N-dimethylamino) ethyl; 3- (N, N-dimethylamino 1aminolpropyl; 4- (N, N-dimethylamino) butyl; 5- (N, N-dimethylamino) penti1e; 4- (N, N-diethylamino) buti1e; 5- (N, N -diethylamino) pentyl; 5- (N, N-diisopropylaminolpentyl; 3- (N-ethylamino) propi1e; 4- {N-methylamino) butyl; 4- (N, N-dipropylamino) butyl; 2- {N, N- diisopropyl amino) ethyl; 6- (N-hexenyl

I am :

aziridine; pyrrolidine; piperidine; morpholine; thiomorpholine; piperazine; 4-methylpiprazine; 4-ethylpiperazine; etc.

Examples of acids containing phosphorus are:

hypophosphorous acid; phosphorous acid; phosphoric acid; pyrophosphoric acid; tripoiiphosphoric acid; ethane-1,1,2-trifo acid

Specific salts of the compounds of formula (I) advantageously usable in the compositions of the present invention are reported in the examples which follow the present description.

The salts constituting component (b) can be prepared with the procedures described in detail in a copending Italian patent application in the name of the Applicant.

In short, the aforesaid salts can be synthesized by reacting in the presence of a suitable solvent (such as for example water, methyl alcohol, ethyl alcohol, acetonitri1e, etc.) at temperatures between 0 ° C and the boiling point of the solvent used, n moles of a 2,4,6-triamino-1,3,5-triazine derivative of general formula (I):

where <η> and the substituents from R a have the previously defined meaning, with one mole of an acid containing phosphorus, or in the absence of solvent and with an excess of the acid containing phosphorus, if the latter can act as a solvent , at temperatures between 0 and 150 ° C.

The saline product formed can be easily separated from the reaction mass by filtration or by distillation of the solvent.

S1 generally obtain products of good quality in the form of white crystalline powder, which can be used in self-extinguishing polymeric compositions without further purification.

Many of the Intermediates of general formula (I) are known; however, they can be easily summarized according to the general method outlined below:

or as reported in the Italian patent application n ° 21066 A / 89 of 03.07.89 filed by the Applicant.

Among the phosphates which can be used in addition to component (b), ammonium polyphosphates are preferred which fall within the general formula in which n represents an integer equal to or greater than 2; preferably the molecular weight of the polyphosphates must be sufficiently high to ensure low solubility in water. Indicatively, n preferably ranges from 2 to 500.

The composition of polyphosphates having the above formula, in which n is a sufficiently large number and preferably between 5 and 500, is practically that which corresponds to the formula of metaphosphates

An example of such polyphosphates is the one known by the trade name of "Exolit 422" (produced and sold by the Hoechst Company) and having the composition in which n is greater than 50; another example is the product known under the trademark "Phos-Chek P / 30" (Monsanto Chemical) and having a similar composition.

Another advantageously usable polyphosphate, especially due to its reduced solubility in water, is the one known under the trade name of "Exolit 462" (produced and sold by Hoechst) and corresponding to Exolit 422 microencapsulated in melamine-formaideid resin.

Other usable phosphates are those deriving from amines, such as for example dimethylammonium or diethylammonium phosphate, ethylenediamine phosphate, melamine ortho- or pyrophosphate.

Among the polymers usable in the compositions of the present invention, the polymers or copolymers of the olefins of general formula R-CH = CH2 where R is a hydrogen atom or a C1-C8 alkyl or aryl radical, in particular: 1. isotactic polypropylene or predominantly isotactic;

2. HDPE, LLDPE, LDPE polyethylene;

3. crystalline copolymers of propylene with minor proportions of ethylene and / or other alpha-olefins, such as for example 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene;

4. heterophasic compositions comprising (A) a homopathic fraction of propylene or one of the copolymers referred to in point (3) and (B) a copolymer fraction formed by elastomeric copolymers of ethylene with an alpha-olefin, possibly containing proportions smaller than a diene, where the alpha oleflna is preferably selected from propylene and 1-butene;

5. elastomeric copolymers of ethylene with alpha olefins possibly containing smaller proportions of a diene.

Examples of the most commonly present dienes in the aforementioned elastomeric copolymers are butadiene, ethylidene-norbornene, hexadlene 1-4.

Among the polymers of olefins having the formula R-CH = CH2 in which R is an aryl radical, "crystal" and shockproof polystyrene are preferred.

Other examples of commonly usable polymers are ABS and SAN copolymers, polyurethane (polyester and polyether), polyethylene terephthalate and polybutylenterephthalate. The self-extinguishing compositions of the present invention can be prepared according to known methods: for example, the ammonium and / or amine phosphate is first intimately mixed with one or more finely ground salts of the compounds of general formula (I) (preferably with particles lower than 70 microns) and the mixture thus obtained is added to the polymer 1 in a turbo mixer to form a homogeneous mixture which is extruded and granulated. The granular product thus obtained can be transformed into various articles, according to any of the known molding techniques.

The flame retardant additives of the present invention are also suitable for use in the field of fire retardant paints.

The following examples illustrate without limiting the characteristics of the invention.

EXAMPLE 1

184.5 g of cyanuric acid chloride and 800 cm3 of acetone are charged into a 3 liter reactor, equipped with stirrer, thermometer, dropping funnel, reflux coolant and heating bath.

It is stirred by heating at 40 ° C until a solution is obtained, then 284 g of an ammonia solution at 30% by weight are added in 1 hour and 30 minutes, maintaining the temperature at 40 ° C. The mixture is then heated to 45 ° C and maintained for 4 hours at this temperature.

After cooling, the formed product is filtered and washed on the filter with water.

After drying in an oven at 50-60 ° C under vacuum, 113 g of the intermediate (III) are obtained:

as a white, infusible crystalline powder, having a chlorine content equal to 24.12% (theoretical = 24.36%).

The structure of this compound was also confirmed by IR spectroscopic analysis.

In a 1 liter reactor equipped with stirrer, thermometer, loading funnel, reflux coolant and heating bath, 72.8 g of intermediate (III), 350 g of water are loaded and then, under stirring, 44 g of piperldine: -It is heated to the boil and is kept refluxing for 4 hours.

It is then left to reflux further for 8 hours, adding 20 g portions of sodium hydrate to 50 g of water, in order to maintain the pH between 7 and 8.

It is cooled to room temperature and the formed product is filtered, washing on the filter with water.

After drying in an oven at 60 ° C under vacuum, 90 g of 2,4-diammiπο-6-piperidino-1,3,5-triazine are obtained, as a white crystalline powder having m.p. = 215-217 ° C (m.p. = melting point).

In the same 1 liter reactor, 77.6 g of 2,4-diamino-6-piperidino-1,3,5-triazine, 400 cm of water and, under stirring, 48.4 g of 85% phosphoric acid are introduced. weight.

The mixture is heated to 80 ° C and is kept at this temperature for 4 hours.

After cooling to 10 ° C, the formed product is filtered and washed on the filter with water.

After drying in an oven at 100 ° C, 96 g of the product are obtained:

as a white crystalline powder having m.p. <:> 228-230 ° C and with a phosphorus content equal to 10.52% (theoretical: 10.61%).

EXAMPLE 2

Into a 0.5 liter reactor, equipped as in example 1, 49.0 g of the intermediate (III), 150 cm of water and 26.2 g of 2-methoxyethylamine are charged.

The mass is heated to boiling and left to reflux for 4 hours.

A solution consisting of 14 g of sodium hydrate in 50 cm of water is then added in 20 minutes.

After a further stirring of 30 minutes, the water distillation is started; the residual mass is subsequently treated with three portions of 100 cm each of acetonitrile in order to extract the organic product.

By subsequent distillation of the solvent 52.5 g of 2,4-diamino-6- {2-methoxyethyl) amino-1,3,5-triazine are obtained as a white powder having m.p. = 166-169 ° C.

In the same 1 liter apparatus in Example 1, 52.5 g of 2,4-diamino-6- (2-methoxyethyl) amino-1,3,5-triazine, 600 cm of acetonitrile are loaded and, under stirring, 34.5 g of 85% by weight phosphoric acid.

The mass is heated to the boil and is kept under reflux for 4 hours.

After cooling to room temperature, the formed product is filtered and washed on the filter with acetonitrile.

After drying in an oven at 100 ° C, 78 g of

as a white crystalline powder, having m.p. = 186-188 ° C, and containing 11.0% phosphorus (theoretical: 10.98%).

EXAMPLE 3

In the same 1 liter apparatus described in the example 91 g of the intermediate (III), 240 cm of toluene and 110 g of morpholine are loaded.

The mixture is heated to 65-70 ° C and is kept at this temperature for 2 hours; it is then heated to boiling and left to reflux for 1 hour.

It is allowed to cool to room temperature and then the product formed is isolated by filtration. The cake is washed abundantly with water and, after drying, 92 g of 2,4-diamino-6-morpholino-1,3,5-triazine are obtained as a white crystalline powder having m.p. = 248-250 ° C.

In a 0.5 liter reactor equipped as in example 1, 39.2 g of 2,4-diamino-6-morpholino-1,3,5-triazine 250 cm of acetonitrile are introduced and, under stirring, 24, 2 g of 85% by weight phosphoric acid.

It is heated to the boil and is kept under reflux for 8 hours.

Then proceeding as described in example 2, 57 g of product are obtained:

as a white crystalline powder, having m.p. = 250-252 ° C and phosphorus content equal to 10.5% (theoretical: 10.54%).

EXAMPLE 4

In a 1 liter reactor equipped as in example 1,

72.8 g of the intermediate (III), 250 cm of water and, under stirring, 104 g of thiomorpholine are added.

The mass is heated to boiling and kept under reflux for 8 hours.

It is cooled to room temperature and the formed product is filtered, washing the cake with water.

After drying in an oven at 100 ° C 90.2 g of 2,4-diamino-6-thiomorpholino-1,3,5-triazine are obtained as a white crystalline powder having m.p. = 237-239 ° C.

In the same 1 liter apparatus, 41.4 g of 2,4-diamino-6-thi omorph olino-1,3,5-tri azine, 300 cm of water and, under stirring, 32.5 g of phenylphosphonic acid are loaded .

The mixture is heated to 80 ° C and is kept at this temperature for 6 hours.

It is cooled to room temperature and then the product formed is filtered by washing on the filter with a little water.

After drying in an oven at 100 ° C, 64.7 g of the product are obtained:

as a white crystalline powder having m.p. = 265-269 ° C and phosphorus content equal to 8.143⁄4 (theoretical: 8.38%).

EXAMPLE 5

In the same 3 liter apparatus of Example 1, 136 g of the intermediate (III) and 800 cm of xylene are loaded.

The suspension is heated to 120 ° C and 302 g of the ethyl ester of N-piperazincarboxylic acid are added in 1 hour.

It is kept at 125-130 "C for 2 hours, then it is cooled to room temperature and the product formed is filtered by washing the cake first with xylene and then, abundantly, with water

After drying in an oven at 100 ° C, 230 g of the intermediate (IV) are obtained:

as a white crystalline powder having m.p. = 210-215 ° C.

The structure of the intermediate (IV) was also confirmed by NMR analysis.

In the same apparatus 1000 cm of acetic acid, 620 g of acetic solution of hydrobromic acid at 33% by weight and 120 g of the intermediate (IV) are loaded.

The mixture is heated to 95 ° C and is kept under stirring at this temperature for 6 hours.

It is subsequently cooled to room temperature and the product formed is filtered by washing on the filter with acetic acid.

The squeezed cake is then taken up in a 2 liter glass with 500 cm of water and added, under stirring, with a 50% by weight sodium hydrate solution until reaching the pH value equal to 11.

The mixture is left under stirring for another hour, then the formed product is filtered by washing abundantly on the filter with water.

After drying in an oven at 100 ° C, 60 g of 2,4-diamino-6-piperazino-1, 3,5-triazine are obtained as a white powder having m.p. = 262-268 ° C.

106.4 g of tetrasodium pyrophosphate and 600 cm of water are loaded into the same 1 liter apparatus of example 1, equipped however with a cooling bath.

It is cooled from the outside to 5 ° C, then 158 g of hydrochloric acid at 37% by weight are added to obtain a solution.

To this solution, again at a temperature of 5 ° C, 78 g of 2,4-diamino-6-piperazino-1,3,5-triazine are added.

It is left under stirring for 2 hours at the same temperature of 5 ° C, then it is heated to 10 ° C and maintained at this new value for 3 hours.

It is cooled to 2 ° C and the product formed is separated by filtration, washing the cake on the filter with a little cold water.

After drying in an oven at 100 ° C, 102 g of the product are obtained:

as a white crystalline powder having m.p. = 295-298 ° C and phosphorus content equal to 16.8% (theoretical: 16.61%).

EXAMPLE 6

184.5 g of cyanuric acid chloride and 1300 cm of methylene chloride are introduced into the same 3-liter apparatus described in example 1, but initially equipped with a cooling bath.

Cooling from the outside, 87.2 g of morpholine and 40 g of dissolved sodium hydrate are fed simultaneously over a period of 3 hours, maintaining the pH between 5 and 7 and the temperature between 0 and 3 ° C. of water.

It is kept at a temperature of 0-3 ° C for a further 3 hours, then the aqueous phase is separated.

By distillation of methylene chloride, 230 g of the intermediate (V) are obtained:

as a white crystalline powder you have m.p. = 155-157 ° C; titer higher than 98% (determined by gas chromatography) and chlorine content equal to 29.87% (theoretical: 30.21%).

In a 0.5 liter reactor, equipped as in example 1, 100 g of a 30% by weight solution of ammonium-3 are charged

niaca, 100 cm of water and 70.5 g of the intermediate (V).

The mixture is heated to 50 ° C and is kept for 7 hours at this temperature; it is allowed to cool to room temperature, the obtained product is filtered and washed with water.

By drying the cake 58 g of the intermediate (VI) are obtained:

as a white crystalline powder having m.p. = 189-191 ° C and chlorine content equal to 16.28% (theoretical: 16.47%).

The structure of intermediates (V) and (VI) was also confirmed by IR spectroscopic analysis.

In the same apparatus described above, 58 g of the intermediate (VI) and 300 g of water are charged and then, under stirring, 18 g of 2-aminoethanol.

It is heated to the boil and is kept under reflux for 3 hours.

It is then left to reflux further for 3 hours by adding 11.8 g of sodium hydrate in 50 g of water portions in order to maintain the pH between 7 and 8.

The mass is cooled, the obtained product is filtered and the cake is washed with water.

After drying, 58 g of 2-amino-4- (2-hydroxyethyl) amino-6-morpholino-1,3,5-triazine are obtained, as a white powder having m.p. = 159-161 ° C.

In a 1 liter reactor equipped as in example 1, 328 g of phosphorous acid and 82 g of acetonitri1e are loaded.

The reaction mixture is gradually heated up to 160 ° C over a time of 6 hours.

A white crystalline product is formed. It is then cooled to 80 ° C and 500 cm3 of water are added to the mass under good stirring, then it is allowed to cool to room temperature.

The product formed is separated by filtration and washed on the filter with a little water.

After drying the cake, 290 g of 1-aminoethane-1, 1-diphosphonic acid are obtained, as a white crystalline powder having m.p. = 265-270 ° C (with decomposition) and phosphorus content equal to 29.4% (theoretical: 30.24%)

In a 0.5 liter reactor equipped as in example 3

1, 200 cm of water, 36 g of 2-amino-4- (2-hydroxythiet1) amino-6-morpholino-1,3,5-triaz1na and 16 g of 1-aminoethane-1,1- diphosphonic.

The mass is heated to 80 ° C and maintained at this temperature for 1 hour, then the distillation of the solvent is started.

By drying the solid residue on distillation in an oven at 100 ° C, 51.6 g of the product are obtained:

as a white crystalline powder having m.p. = 144-148 ° C and phosphorus content equal to 8.8% (theoretical: 9.04%).

EXAMPLE 7

In a 0.5 liter reactor equipped as in example 1, 39.2 g of 12,4-diamm1no-6-morphol1no-1,3,5-triazine (prepared as described in example 3), 300 cm of ethyl alcohol and, under stirring, 17.2 g of phosphorous acid.

It is left under stirring at room temperature for 8 hours, then the formed product is filtered, washing on the filter with a little solvent.

By drying the cake in an oven at 100 ° C, 55 g of the product are obtained:

as a white crystalline powder having m.p. = 240-244 ° C and phosphorus content equal to 11% (theoretical: 11.13%).

EXAMPLES 8-32

Operating under conditions similar to those described in Examples 1 to 7, the saline products of general formula (II) shown in Table 1 are prepared.

Tables 2 and 3

The tests reported in the above tables relate to polymeric compositions containing the salts prepared according to the preceding examples.

Specimens in the form of platelets having a thickness of about 3 mm were prepared by printing mixtures of granular polymer and additives in a MOORE plate press, operating for 7 minutes at a pressure of 40 kg / cm.

The self-extinguishing level was determined on the plates thus obtained by measuring the oxygen index (L.O.I. according to the ASTM D-2863/77 standard) in a Stanton Redcroft device, and applying the "Vertical Burning Test" which allows to classify the material to the three levels 94 V-0, 94 V-l and 94 V-2 according to UL 94 standards (published by the "Underwriters Laboratories" -USA).

Table 2 shows the values obtained using an isotactic polypropylene in flakes having a Melt Flow Index equal to 12 and an Insoluble fraction in boiling n-heptane equal to 96% 1n weight.

Table 3 shows the values obtained using a low density polyethylene in granules having a Melt Flow Index equal to 7; a polystyrene in granules containing 5% by weight of butadiene rubber and having a Melt Flow Index equal to 9; a thermoplastic polyurethane both polyester (ESTANE 54600 by Goodrich) and polyether (ESTANE 58300 <R> by Goodrich) in granules having a specific weight of 1.19 and 1.10 g / cm respectively; an ethylene-propylene elastomeric copolymer having a percentage content by weight of propylene equal to 45; an acrylonitrile-butadiene-styrene thermo-limer having a specific weight equal to 1.06 g / cm, Melt Flow Index equal to 1.6 and containing about 40% of acrylonitrile and styrene and 20% of butadiene.

EXAMPLE 105 (comparison)

Operating according to the methods used in the examples from n. 33 to n. 77, however, using the phosphate (1: 1) of 2,4,6-triamino-1,3,5-triazine as nitrogenous compound, the following composition is prepared:

Using the aforesaid composition, specimens were prepared which were subjected to self-extinguishing tests according to the methods described above.

S1 the following results are obtained:

L.O.I. : 23.5

UL 94 (3mm): class B (the specimen burns).

EXAMPLE 106 (for comparison)

Operating as in example 105, the composition specified below is prepared:

Using the aforesaid composition s1, specimens are prepared which have been subjected to self-extinguishing tests according to the methods described above. The following results were obtained: L.O.I. : 22.5

UL 94 (3mm): class B (the specimen burns).

Claims (1)

propylene and 1-butene; 5) elastomeric copolymers of ethylene with alpha olefins possibly containing smaller proportions of a diene. 13. Printed articles, obtained from the compositions of the preceding claims.